1. Field of the Invention
The present invention relates to a wire collision sensor system for vehicle. The wire collision sensor system senses a vehicle collision load by use of a wire.
2. Description of Related Art
Unexamined Japanese Patent Publication No. 2004-212281, which corresponds to US 2004/0129479 A1, discloses the wire collision sensor system, which senses an increase of a tensile force of a wire at a time of a vehicle collision. The wire is horizontally spanned along a front side of a bumper reinforcement at a predetermined level of the tensile force.
An invention according to the Unexamined Japanese Patent Publication No. 2004-212281 measures a tensile force variation, which is caused by deformation of the bumper reinforcement at the time of the vehicle collision, by use of tensile force sensors that are connected with corresponding ends of the wire. In a case where the invention measures a collision of a collision body with a small mass (e.g., a pedestrian), the deformation of the bumper reinforcement at the time of the vehicle collision is small. Thus, this may cause a disadvantage, such as deterioration of a degree of sensing accuracy. Also, there may be a disadvantage of sensing latency. The collision body collides with the bumper, and a collision load is transmitted from the bumper to the bumper reinforcement. Then, the bumper reinforcement is deformed. The collision or the collision load are not sensed until the wire tensile force is changed as a result of the deformation of the bumper reinforcement. Likewise, the sensing latency occurs.